FIREWALL ========= .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is a Firewall?** A firewall is a network security system—either hardware, software, or both—that monitors and filters incoming and outgoing network traffic based on an organization’s previously established security policies. It acts as a barrier between a trusted network and untrusted external networks (like the internet). .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Why is a Firewall Useful?** * Protects networks from unauthorized access and cyber threats. * Monitors and controls traffic based on defined rules. * Prevents malware, exploits, and intrusion attempts. * Supports compliance with security standards (e.g., PCI-DSS, HIPAA). * Enables segmentation of networks for control and isolation. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How It Works:** * Traffic arrives at the firewall from internal or external sources. * Rules are evaluated – based on IP address, port, protocol, etc. * A decision is made: allow, deny, or log the traffic. * Traffic is forwarded or blocked accordingly. * Logs and alerts are generated for monitoring and auditing. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Where is a Firewall Used?** * Enterprise networks – to protect internal infrastructure. * Cloud environments – as virtual firewalls (e.g., AWS Security Groups, Azure NSGs). * Home networks – within routers or personal firewall applications. * Data centers – to segment and secure workloads. * Industrial systems – for securing OT/SCADA networks. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Which OSI Layer Does This Concept Belong To?** * Firewalls operate primarily at **Layer 3 (Network)** and **Layer 4 (Transport)** of the OSI model. * They analyze IP addresses, TCP/UDP ports, and protocols. * **Next-Generation Firewalls (NGFWs)** may also inspect traffic at **Layer 7 (Application Layer)** such as HTTP, DNS, or FTP. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow Topics in this section, * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`FIREWALL Version&RFC Details ` * :ref:`FIREWALL Basic Setup on Ubuntu using IPv4 ` * :ref:`FIREWALL Basic Setup on Ubuntu using IPv6 ` * :ref:`FIREWALL Protocol Packet Details ` * :ref:`FIREWALL Usecases ` * :ref:`FIREWALL Basic Features ` * :ref:`FIREWALL Feature : Packet Filtering ` * :ref:`FIREWALL Feature : Stateful Inspection ` * :ref:`FIREWALL Feature : Access Control ` * :ref:`FIREWALL Feature : Logging and Monitoring ` * :ref:`FIREWALL Feature : NAT ` * :ref:`FIREWALL Feature : VPN Support ` * :ref:`FIREWALL Feature : Application Layer Filtering ` * :ref:`FIREWALL Feature : Intrusion Detection/Prevention ` * :ref:`FIREWALL Feature : Web Filtering ` * :ref:`FIREWALL Feature : High Availability, ` * :ref:`Reference links ` .. _FIREWALL_step1: .. tab-set:: .. tab-item:: Learnings in this section * In this section, you are going to learn .. _FIREWALL_step2: .. tab-set:: .. tab-item:: Terminology * Terminology .. _FIREWALL_step3: .. tab-set:: .. tab-item:: Version Info * Version Info .. _FIREWALL_step5: .. tab-set:: .. tab-item:: FIREWALL Version&RFC Details .. csv-table:: :file: ./FIREWALL/FIREWALL_RFC_Details.csv :widths: 10,10,10,30,40 :header-rows: 1 .. _FIREWALL_step19: .. tab-set:: .. tab-item:: FIREWALL Basic Setup on Ubuntu using IPv4 * Setup .. _FIREWALL_step20: .. tab-set:: .. tab-item:: FIREWALL Basic Setup on Ubuntu using IPv6 * Setup .. _FIREWALL_step6: .. tab-set:: .. tab-item:: FIREWALL Protocol Packet Details **TCP Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_1.csv :widths: 10,20,30,10 :header-rows: 1 **UDP Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_2.csv :widths: 10,20,30,10 :header-rows: 1 **ICMP Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_3.csv :widths: 10,20,30,10 :header-rows: 1 **HTTP/HTTPS Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_4.csv :widths: 10,20,30,10 :header-rows: 1 **DNS Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_5.csv :widths: 10,20,30,10 :header-rows: 1 **SMTP Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_6.csv :widths: 10,20,30,10 :header-rows: 1 **SNMP Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_7.csv :widths: 10,20,30,10 :header-rows: 1 **GRE/IPSec Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_8.csv :widths: 10,20,30,10 :header-rows: 1 **DHCP Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_9.csv :widths: 10,20,30,10 :header-rows: 1 **FTP Packet** .. csv-table:: :file: ./FIREWALL/FIREWALL_Protocol_Packet_10.csv :widths: 10,20,30,10 :header-rows: 1 .. _FIREWALL_step7: .. tab-set:: .. tab-item:: FIREWALL Usecases .. csv-table:: :file: ./FIREWALL/FIREWALL_Usecases.csv :widths: 10,20,30 :header-rows: 1 .. _FIREWALL_step8: .. tab-set:: .. tab-item:: FIREWALL Basic Features .. csv-table:: :file: ./FIREWALL/FIREWALL_Features.csv :widths: 10,10,30 :header-rows: 1 .. _FIREWALL_step9: .. tab-set:: .. tab-item:: FIREWALL Feature : Packet Filtering **Packet Filtering - Testcases** .. csv-table:: :file: ./FIREWALL/FIREWALL_Feature-1_Packet_Filtering_Testcase.csv :widths: 10,10,30,20 :header-rows: 1 .. _FIREWALL_step10: .. tab-set:: .. tab-item:: FIREWALL Feature : Stateful Inspection **Stateful Inspection - Testcases** .. csv-table:: :file: ./FIREWALL/FIREWALL_Feature-2_Stateful_Inspection_Testcase.csv :widths: 10,10,30,20 :header-rows: 1 .. _FIREWALL_step11: .. tab-set:: .. tab-item:: FIREWALL Feature : Access Control **Access Control - Testcases** .. csv-table:: :file: ./FIREWALL/FIREWALL_Feature-3_Access_Control_Testcase.csv :widths: 10,10,30,20 :header-rows: 1 .. _FIREWALL_step12: .. tab-set:: .. tab-item:: FIREWALL Feature : Logging and Monitoring **Logging and Monitoring - Testcases** .. csv-table:: :file: ./FIREWALL/FIREWALL_Feature-4_Logging_and_Monitoring_Testcase.csv :widths: 10,10,30,20 :header-rows: 1 .. _FIREWALL_step13: .. tab-set:: .. tab-item:: FIREWALL Feature : NAT **NAT - Testcases** .. csv-table:: :file: ./FIREWALL/FIREWALL_Feature-5_NAT_Testcase.csv :widths: 10,10,30,20 :header-rows: 1 .. _FIREWALL_step14: .. tab-set:: .. tab-item:: FIREWALL Feature : VPN Support **VPN Support - Testcases** .. csv-table:: :file: ./FIREWALL/FIREWALL_Feature-6_VPN_Support_Testcase.csv :widths: 10,10,30,20 :header-rows: 1 .. _FIREWALL_step15: .. tab-set:: .. tab-item:: FIREWALL Feature : Application Layer Filtering **Application Layer Filtering - Testcases** .. csv-table:: :file: ./FIREWALL/FIREWALL_Feature-7_Application_Layer_Filtering_Testcase.csv :widths: 10,10,30,20 :header-rows: 1 .. _FIREWALL_step16: .. tab-set:: .. tab-item:: FIREWALL Feature : Intrusion Detection/Prevention **Intrusion Detection/Prevention, - Testcases** .. csv-table:: :file: ./FIREWALL/FIREWALL_Feature-8_Intrusion_Detection_Prevention_Testcase.csv :widths: 10,10,30,20 :header-rows: 1 .. _FIREWALL_step17: .. tab-set:: .. tab-item:: FIREWALL Feature : Web Filtering **Web Filtering - Testcases** .. _FIREWALL_step18: .. tab-set:: .. tab-item:: FIREWALL Feature : High Availability **High Availability - Testcases** .. csv-table:: :file: ./FIREWALL/FIREWALL_Feature-10_High_Availability_Profiles_Testcase.csv :widths: 10,10,30,20 :header-rows: 1 .. _FIREWALL_step21: .. tab-set:: .. tab-item:: Reference links * Reference links